code: def test_spline():
      theta = np.linspace(-4 * np.pi, 4 * np.pi, 100)
      z = np.linspace(-2, 2, 100)
      r = z**2 + 1
      x = r * np.sin(theta)
      y = r * np.cos(theta)
  
      points = np.column_stack((x, y, z))
      spline = pv.Spline(points, 1000)
      assert spline.n_points == 1000
  
imports: import numpy
  import pytest
  import vtk
  import pyvista
  from pyvista.core.errors import PyVistaDeprecationWarning
label_desc: Use image node_id 1 for calling a global function with example usage: test_spline() without return types